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PURPOSE AND METHODS: Botrytis cinerea is the primary disease affecting cucumber production. It can be managed by applying pesticides and cultivating disease‐resistant cucumber strains. However, challenges, such as drug resistance in pathogenic bacteria and changes in physiological strains, are obstacles in the effective management of B. cinerea. Nano‐selenium (Nano‐Se) has potential in enhancing crop resistance to biological stress, but the exact mechanism for boosting disease resistance remains unclear. Here, we used metabolomics and transcriptomics to examine how Nano‐Se, as an immune activator, induces plant resistance. RESULT: Compared with the control group, the application of 10.0 mg/L Nano‐Se on the cucumber plant's leaf surface resulted in increased levels of chlorophyll, catalase (10.2%), glutathione (326.6%), glutathione peroxidase (52.2%), cucurbitacin (41.40%), and metabolites associated with the phenylpropane synthesis pathway, as well as the total antioxidant capacity (21.3%). Additionally, the expression levels of jasmonic acid (14.8 times) and related synthetic genes, namely LOX (264.1%), LOX4 (224.1%), and AOC2 (309.2%), were up‐regulated. A transcription analysis revealed that the CsaV3_4G002860 gene was up‐regulated in the KEGG enrichment pathway in response to B. cinerea infection following the 10.0 mg/L Nano‐Se treatment. DISCUSSION: In conclusion, the activation of the phenylpropane biosynthesis and branched‐chain fatty acid pathways by Nano‐Se promotes the accumulation of jasmonic acid and cucurbitacin in cucumber plants. This enhancement enables the plants to exhibit resistance against B. cinerea infections. Additionally, this study identified a potential candidate gene for cucumber resistance to B. cinerea induced by Nano‐Se, thereby laying a theoretical foundation for further research in this area. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The polylactic acid-glycolic acid copolymer (PLGA) has been proven to be applicable in medicine, but there is limited research on its application and safety in the agricultural field. In this paper, thifluzamide PLGA microspheres were prepared via phacoemulsification and solvent volatilization, using the PLGA copolymer as the carrier and thifluzamide as the active component. It was found that the microspheres had good slow-release performance and fungicidal activity against Rhizoctonia solani. A comparative study was conducted to show the effect of thifluzamide PLGA microspheres on cucumber seedlings. Physiological and biochemical indexes of cucumber seedlings, including dry weight, root length, chlorophyll, protein, flavonoids, and total phenol content, indicated that the negative effect of thifluzamide on plant growth could be mitigated when it was wrapped in PLGA microspheres. This work explores the feasibility of PLGA as carriers in fungicide applications. [ABSTRACT FROM AUTHOR]